PB1977: SPECTRUM OF INFECTIOUS COMPLICATIONS FOLLOWING TRANSPLANTATION OF AUTOLOGOUS BLOOD STEM CELLS IN PATIENTS WITH MULTIPLE MYELOMA
Authors: A. Abakumova, L. Mendeleeva, G. Klyasova, M. Solovev, M. Firsova, E. Makunina, E. Mamaeva, A. Startsev
Journal: HemaSphere (2022)

Background: Transplantation of autologous blood stem cells (auto-HSCT) is one of the key methods in multiple myeloma (MM) treatment recommended to patients under 65 years of age and good somatic status. The early post-transplantation period is associated with the development of deep myelotoxic agranulocytosis, disruption of mucous membranes of gastrointestinal tract and high risk of infectious complications. Aims: Determine the incidence of infectious complications and the spectrum of pathogens in MM patients after autologous transplantation. Methods: Our study includes 111 MM patients (51 male) aged 19 to 65 (median age 53) who performed an auto-HSCT between 2018 and 2020. In 99 patients Durie-Salmon stage was considered as III, in 1 - as II and in 11 - as I. Myeloma nephropathy was observed in 23 patients, programmed hemodialysis in 4. Prior to the auto-HSCT 42 patients had reached the CR, 48 - VGPR, 15 - PR, 4 - stabilisation, 2 - progression. Hematopoietic stem cells were mobilized and 2,1-23,15x106/kg CD34+ cells (median 7,7) collected. Conditioning was performed with melphalan 200mg/m2 (n=93) and 140 mg/m2 (n=15), due to myeloma nephropathy and hemodialysis. Agranulocytosis lasted from 6 to 97 days (median 12). The colonization of non-sterile compartment was investigated before and in agranulocytosis. In case of the febrile fever, Bactec blood culture systems and chest CT were performed, in case of the oral mucositis - microbiological mucus examination from tonsils and the throat back wall. If pneumonia was established by CT, fibrobronchoscopy was performed with microbiological, molecular-biological and PCR examinations of bronchoalveolar lavage (BAL). Viral blood profile was investigated by PCR for CMV, HHV-6, Herpes simplex viruses. During neutropenia all patients were given antiviral prophylaxis by valaciclovir. Due to infection developing, broad-spectrum antibiotics were prescribed. Results: Infectious complications in the early post-transplant period was noted in 94.6% of MM patients. The most frequent were oral mucositis (95.5%) and necrotic enteritis (85.6%). Microbiological analysis of non-sterile compartment in 101 patients revealed 52 cases of E.coli without ESBL, 35 - with E.coli ESBL. In agranulocytosis, 93 cases were detected: E.coli without ESBL (n=32), E.coli ESBL (n=19). Bacteriemia was identified in 18 patients: 7 cases of gram-positive and 11 of gram-negative. Pneumonia, confirmed by chest CT, was detected in 17 (15.3%) patients, and in 8 cases fibrobronchoscopy was performed. The pathogens etiology was established in 5 patients - gram-positive (n=3) and gram-negative (n=2). Viral infection associated with HHV-6 was found in 8%. Analysing non-sterile compartment before the therapy and in case of bloodstream infection, they matched in 7 cases, a difference was found in 4 cases (C.koseri without ESBL, P.aeruginosa, C.putigena). In 110 patients all infections were successfully cured and patients were discharged satisfactorily. Only one patient died at +9 day of auto-HSCT from bilateral pneumonia caused by S. aureus and bacteriemia associated with P. aeruginosa and S. aureus. Image:Summary/Conclusion: In our study, the most frequent infectious complications in patients with MM in the early post-transplantation period, were oral mucositis and necrotic enteritis, mainly I-II degree of severity. Complications, such as pneumonia and bacteriaemia, developed in 32%. Viral infections were detected in 8% of patients and associated with HHV6. Early post-transplant mortality was 0.9%.